The Raman spectrum of has been measured for various scattering configurations in crystals with different compositions. The comparison between spectra recorded for the congruent and the nearly stoichiometric crystals shows significant differences in the shape and the number of Raman peaks. The analysis of results leads to a new and complete assignment of the long-wavelength optical phonons in .

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Two bis(1-pyrazolyl)alkane ligands, bis(3,5-dimethyl-1-pyrazolyl)methane and bis(4-iodo-3,5-dimethyl-1-pyrazolyl)methane, and their copper(II) complexes, bis(3,5-dimethyl-1-pyrazolyl)methanedinitratocopper(II) [CuL1(NO3)2] and bis(4-iodo-3,5-dimethyl-1-pyrazolyl)methanedinitratocopper(II) [CuL2(NO3)2] x 2H2O, were prepared. Physiochemical properties of the copper(II) complexes were studied by spectroscopic (UV-vis, IR, EPR) techniques and cyclic voltammetry. Spectroscopic analysis revealed a 1:1 stoichiometry of ligand:copper(II) ion and a bidentate coordination mode for the nitrate ions in both of the complexes. According to experimental and theoretical ab initio data, the copper(II) ion is located in an octahedral hexacoordinated environment. Both complexes were able to catalyze the dismutation of superoxide anion (O2*-) (pH 7.5) and decomposition of H2O2 (pH 7.5) and peroxynitrite (pH 10.9). In addition, both complexes exhibited superoxide dismutase (SOD) like activity toward extracellular and intracellular reactive oxygen species produced by activated human neutrophils in whole blood. Thus, these complexes represent useful SOD mimetics with a broad range of antioxidant activity toward a variety of reactive oxidants.

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Two new axial Fe'" centres, arising after reduction of stoichiometric lithium niobate crystals grown horn melts containing &O. were discovered and investigated by EPR. Their b: crystal field parameters ax equal to 495 and 688 ( x cm-I) and are thus much smaller lhan b; for the axial F&t cenlre., 1660 x IO-' cm-I, which had been studied before. The models of Fe3+ cenues in lithium niobate and lithium tantalate crystals ax "pared and the possible s h u -e and Fei,+,-KE-of the new centres are discussed.